After completing its main mission, CubeSat will approach Earth on the evening of Tuesday, May 16, and NASA’s Eyes in the Solar System will watch as it bids farewell. NASA’s Lunar Flashlight mission to the Moon is over, but the briefcase-sized spacecraft will soon pass near Earth before heading into deep space. At 9:44 PM PDT on Tuesday, May 16 (Wed 17th, at 12:44 PM ET), CubeSat will pass approximately 40,000 miles (65,000 kilometers) above the surface of our planet.

NASA’s Eyes on the Solar System 3D imaging instrument will track the small spacecraft in real time, giving users a front-row seat for flight. (The device also provides a wealth of information about the spacecraft, including its orbit and future journey into deep space.) Additionally, the CubeSat may be within range of amateur astronomers’ telescopes in the Southern Hemisphere.

“As the Moon Flashlight approaches, it can reflect enough sunlight from its solar panels that it can be seen in a modest telescope,” said Barbara Cohen, principal investigator of the Moon Beacon at NASA’s Goddard Space Flight Center in Greenbelt, Maryland. “Depending on the direction and position, it can be a point that moves up to magnitude 5 or 6.”

A 3D model of NASA’s Moonlight can be viewed in the fully interactive Eyes of the Solar System section. Zoom out and use the fast forward and rewind controls to follow CubeSat as it passes Earth. Image source: NASA/JPL-Caltech

Sunlight reflected from CubeSat solar panels tens of thousands of miles away is visible to those with clear, dark skies. The brightness of an astronomical object can be measured in apparent magnitude. CubeSat, a 5 or 6 magnitude object, can be seen by backyard telescopes as it passes through its closest point on the east coast of Brazil. Observers should use NASA Horizons to check where the Lunar Flashlight will be in the sky.

After its launch on December 11, “Moonlight” was sent along a long circular path far beyond Earth’s orbit. Now, it has come even closer to our planet after being pulled by the combined gravity of the Earth and Moon.

The spacecraft is designed to test new technologies and fill knowledge gaps by exploring permanently shadowed craters at the moon’s south pole. Shortly after launching the Lunar Flashlight, however, the task force discovered that the CubeSat’s four engines were malfunctioning. After months of troubleshooting to rectify the situation, time was running out for the spacecraft to perform the critical maneuvers that would bring it into orbit around Earth with monthly flights from the Moon’s south pole. When it became clear that the Lunar Beacon was unable to reach the correct orbit for Moon observations, NASA announced that it was ending the remainder of its mission. Other systems of the spacecraft are working well and continue to communicate with mission operators. NASA is currently evaluating options for the future of the Lunar Flashlight.

CubeSat will continue its orbit around the Sun after passing Earth. Lunar Flashlight’s orbit will bring it closer to Earth again in November 2037.